If you’re already experienced with weightlifting and train your legs twice a week for 8 weeks with hard sets, your muscles will grow whether you take short breaks between reps or not.

Scientific Claim

In young, resistance-trained individuals, 8 weeks of twice-weekly leg press and leg extension training with 5 sets of 12 repetitions (either as traditional or cluster sets) leads to significant increases in thigh lean tissue mass and rectus femoris muscle thickness, confirming that both protocols are effective for hypertrophy under volume- and effort-matched conditions.

Original Statement

“Statistically significant increases in lean mass after the training intervention in both CS (mean [95% CI 88.5–255.2]; p = 0.002) and TS (201.1 g [95% CI 117.7–284.5]; p < 0.001). Statistically significant increases in muscle thickness in both CS (p < 0.001) and TS (p = 0.012).”

From study:Cluster sets and traditional sets elicit similar muscular hypertrophy: a volume and effort-matched study in resistance-trained individuals

Evidence Quality Assessment

Claim Status

overstated

Study Design Support

Design supports claim

Appropriate Language Strength

association

Can only show association/correlation

Assessment Explanation

The study shows within-subject changes, but without confirmed randomization, causal language like 'leads to' is inappropriate. Only association between training and change can be claimed.

More Accurate Statement

“In young, resistance-trained individuals, 8 weeks of twice-weekly leg press and leg extension training with 5 sets of 12 repetitions (either as traditional or cluster sets) is associated with significant increases in thigh lean tissue mass and rectus femoris muscle thickness, confirming that both protocols are effective for hypertrophy under volume- and effort-matched conditions.”

Evidence from Studies

Supporting (1)

Cluster sets and traditional sets elicit similar muscular hypertrophy: a volume and effort-matched study in resistance-trained individuals

Randomized Controlled Trial

Human

2025 Jun

This study found that doing leg exercises in short bursts with breaks (cluster sets) or in long sets without breaks (traditional sets) both made people’s thighs bigger and stronger—so neither method is better than the other when you do the same total work.

Contradicting (0)

No contradicting evidence found

Source Study

Cluster sets and traditional sets elicit similar muscular hypertrophy: a volume and effort-matched study in resistance-trained individuals

Score: 45

DOI: 10.1007/s00421-025-05712-6

Similar Assertions

Doing leg extensions makes the front thigh muscle grow more evenly along its length than doing squats, which don’t stimulate that muscle as much.

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When people who already lift weights do either short breaks between reps (cluster sets) or long continuous sets (traditional sets), both ways make their muscles grow about the same amount if they work just as hard and do the same total number of reps.

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Doing leg extensions (kicking your leg out while sitting) makes the front thigh muscle right above your knee grow more than doing leg presses (pushing a heavy platform with both legs).

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Doing leg extensions with drop sets (going to failure, then lowering the weight and going again) makes the front part of your thigh muscle grow more than doing regular sets, but only in the upper and middle parts—not the bottom or the side muscles.

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Lifting weights just twice a week for two months is enough to make the upper and middle parts of your thighs bigger—even if you change how you do the sets, as long as you do the same total work.

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